1. The Field of the Invention
This invention relates to systems and methods for gathering and storing data from a variety of sources. More particularly, the present invention relates to systems and methods for acquiring, storing, and averaging data in real time as it is derived from a data generating event.
2. The Prior Art
Electronic systems which are found in science, industry, and society often require that information concerning some event be gathered, stored, manipulated, and analyzed. Such data acquisition systems range from those which gather data at a relatively slow rate to those which must gather very accurate data at a very high rate. For example, sensing the coolant temperature in an automobile engine is a common example of gathering information and displaying the information which can be satisfactorily gathered a few times each second and the accuracy need not be exact. In contrast, a guidance system for a missile may require that very accurate information be gathered, stored, and analyzed billions of times each second.
Most physical phenomenon are best characterized as analog events where changes from one value to the next occur as smooth continuous transitions. Digital information processing techniques, however, are best suited for gathering, storing, and analyzing information.
An analog to digital convertor is an electrical device that converts an analog signal to a digital signal. Once the analog signal has been converted to a digital signal it can be manipulated and stored by computing equipment which is commonly available. For example, it is now common to take the analog signal generated by the coolant temperature sensor in automobiles, pass it through an analog to digital convertor where it is converted to a digital format, and then convey it to a computer which calculates other engine criteria and where the coolant temperature is reported in digits on a dashboard display.
There are numerous applications where digital data from analog to digital convertors is gathered, stored, and analyzed. For example, digital data is encountered in areas such as avionics, radar, industrial measurement and control, medical equipment, chemical analysis equipment, and so forth. An analog to digital converter, by itself, often is fabricated on a single integrated circuit. However, where data is to be stored, manipulated, or analyzed, a data acquisition system, which includes an analog to digital convertor, must be fashioned. In applications where large amounts of digital data must be very accurately gathered and stored, the data acquisition system becomes very complex. The particular configuration of the data acquisition system is dependent upon the end application.
Several criteria are commonly used to evaluate most digital data acquisition systems. One such criteria is its sampling rate, that is, how fast it can convert analog signals to digital signals. Another criteria for data acquisition systems is their data storage capability. Generally, it is very desirable if a data acquisition system can store and preserve large amounts of the data it has accumulated. Those skilled in the art will recognize that designing a data acquisition system which combines large data storage capability with a high sampling rate can be difficult. This is especially true when large (for example, greater than a few megasamples) data storage is required. There are, for example, available data acquisition systems which have sample rates of 100 MHz. Storing data which is gathered at high sampling rates is difficult, especially if the data is to be accumulated for more than a few milliseconds.
A third major criteria of data acquisition systems is averaging capability. It is often advantageous to perform averaging on a given signal, especially when the signal is associated with a repetitive pulse where averaging techniques are readily applied. Averaging of the data provides advantages such as decreasing the amount of storage required, allowing slower storage devices to be used, reducing unwanted random background noise, and increasing the effective resolution of the actual data acquisition system.
In view of the advantages which accrue when averaging techniques are used, some data acquisition systems are optimized to take advantage of averaging. Other data acquisition systems are not optimized to carry out averaging. When averaging is needed, a data acquisition system which is optimized to carry out averaging will perform better than a data acquisition system which is not. Conversely, when averaging is not suitable, a data acquisition system which is not optimized to carry out averaging will perform better than a data acquisition system which is optimized to perform averaging.
In view of the foregoing, it would be an advance in the art to provide a data acquisition system which overcomes the drawbacks present in the art.